"If these were coming out of a smokestack or a tailpipe, they would be regulated," Steinemann said. "If they are in a hand soap or air freshener, they are not."
Industry groups insist their scented products are safe.
"The article unnecessarily alarms the public with insinuations of danger," wrote the International Fragrance Association in response to Steinemann's study.
"Fragrance materials are safe," the statement continued. "The industry is strongly committed to science and safety, spending significant annual resources on peer-reviewed studies and testing of ingredients."
Seventh Generation, a well-known and environmentally minded company that produces personal care and cleaning products, some that are unscented, says it lists every ingredient in its products, including the essential oils it uses as fragrances.
"We use very low levels of fragrances in our products because we recognize that these are volatile organic compounds and that we inhale them," said Martin Wolf, a chemist and director of sustainability at Seventh Generation, in Burlington, Vt. "A company should be proud of what it's putting in its bottles."